Hey Elizabeth! I'm not a native Spanish speaker, but I am a native English speaker (so I can sympathize with you) and my Spanish is pretty decent and I have read a few novels in Spanish (and in other foreign languages). In my opinion, at least for me, I do find that contemporary literature in any foreign language is much easier to understand. Even with a language that shares as much higher vocabulary with English as, say, French, I find it pretty difficult to read without googling a word every at least every 2 or 3 pages. And mind you, my French is my second best language. More contemporary works though, for whatever reason, are much easier to read. When I read a Young Adult novel in Russian, I flew right through it, without needing to use the dictionary more than once every 10 pages or so. If YA is not your thing, perhaps you can try more mature works? I'm currently reading Italian author Elena Ferrante's Neopolitan Novels series in French translation and it's pretty easy for me, perhaps the Spanish translation is also as approachable? If you want something written in Spanish, I've read a couple of books by Elisabet Benavent and they're very readable for me. (But I realize books like that are not everyone's cup of tea). You can certainly try older books too, but I think you might have lower success with them. For what it's worth, I've absolutely loved reading La Sombra del Viento by Zafon, even though I had to search up a word roughly every other page.

Hola Elizabeth,
Te aconsejo que leas un libro llamado CUentos de la selva del autor Mario Quiroga, es una buena iniciación en libros en español.
Saludos,
Adriana.

Si le gusta los clásicos, pero aún Ud no es bastante avanzada para leerlos, tengo una sugerencia. En mi colegio, leemos libros adaptados por EasyReaders. Los libros son escritos para la gente que aprende español, así que hay niveles diferentes por cada libro y se definen algunas palabras. He leído Don Quijote y El Carnaval, y me gustó los dos.